Features Page 79 of 910
IP Line Description, Installation and Maintenance
the call-associated resources are not used, but they still exist on the Call
Server since they are not released. To prevent this, the ten-minute Call Server
ACF timer is introduced for each call. The timer prevents call
processing-related resources from being unnecessarily used when an IP
Phone that had an active call unregisters and never reregisters.
The timer is set if:
• the ACF call status is UNREGISTERED; that is, when both parties go
offline.
• only one of the parties is offline, and the other party does not support
disconnect supervision.

ACF scenarios

Table 13 describes ACF behavior in different scenarios.
Table 13
ACF behaviors (Part 1 of 8)
Scenario Result
TLAN subnet failure:
• A call is established between IP Phones A
and B registered with the same node.
• TLAN subnet goes down.
• The IP Phones detect the connection is
lost and periodically try to reregister.
• The TLAN subnet is up shortly (less than
10 minutes), or an election is called and
another accessible LTPS node acquires
the node IP address. The IP Phones
reregister with the node again.
The call is not lost as the IP Phones
reregister.
In this scenario, the call exists on the Call
Server during the failover time and has the
following transitions:
UNREGISTERED ->HALF-REGISTERED ->
NO ACF